The invention relates to self-heating devices for providing heating by exothermic chemical reactions. Compact, self-heating devices that produce heat through exothermic chemical reactions are known to the art. U.S. Pat. No. 4,397,315 discloses a device having an outer envelope and an inner envelope, with the outer envelope containing sodium thiosulfate, and the inner envelope containing ethylene glycol. The walls of the inner envelope are rupturable, allowing the contents of each envelope to mix. U.S. Pat. No. 5,035,230 discloses a heat pack having two compartments separated by a frangible seal. Potassium permanganate oxidizing agent coated with sodium silicate is provided in one zone of the heat pack, and aqueous ethylene glycol fuel is provided in the other zone. In operation of the device, the seal is compromised to allow the reactants to come in contact with each other.
Devices for producing heat or cold by heat of dilution rather than by chemical reaction are also known. U.S. Pat. No. 3,804,077 describes a heat pack which contains a water soluble chemical (e.g., calcium chloride) and a starch material acting as a gelling agent in one zone, and water in another zone.
An aspect of the invention is a disposable container divided into liquid-containing and liquid-impermeable zones.
A further aspect of the invention is a liquid comprising an oxidizing agent, and another liquid comprising a fuel, each liquid in separate zones.
Another aspect of the invention is a non-fuel gelling agent in at least one of the zones.
Yet another aspect of the invention is a separator disposed between zones containing oxidizing agent, and zones containing fuel.